Rebuilt 860 Lift Cover NOW LIFTS SLOW

[strum456]

I just finished rebuilding the lift cover on my 860. Before the rebuild, it didn't lift high enough and it leaked down pretty bad. I replaced the cylinder o-rings and the cam follower pin. I also replaced all the o-rings that go between the cylinder and the lift cover, etc..

When I first started the tractor, I had no hydraulic lift. No surprise...air I figured. I cracked the bleeder on the pump and it started to work, but really slow and jerky. I proceed to work the lift arms up and down and mess with the bleeder for about 15 minutes, but it still lifts slow. On the plus side, the lift arms go much higher now.

Here are my thoughts.

1. I STILL don't have all the air out???

2. An o-ring did not seal. How on earth would I find out which one?

3. I didn't adjust the linkage properly. I followed the directions in the book, and after a couple hours of messing around, I determined that it would not be possible to get both measurements correct at the same time. Could incorrect adjustment cause slow lifting? I thought it would only affect the range of motion and draft control (which I never use anyway).

 

[Soundguy]

i'd be looking for an oil leak in the back of the sump.

also. is it just slow.. or is it slow and weak?

is the oil foaming any?

 

[strum456]

i'd be looking for an oil leak in the back of the sump.

also. is it just slow.. or is it slow and weak?

is the oil foaming any?

Thanks for the reply. I'm not sure what you mean by "the back of the sump". I am thinking that the sump would be the reservoir and I didn't mess with any lines for the reservoir, except for where they meet the transmission, because I had to split the tractor for other reasons.

Is it slow and weak? I'll have to get back to you on that. It lifts me just as fast as no load. Of course, I weigh a bit less than a 6' brush hog.

Foaming? I noticed a little air coming out of the bleeder, but not white foam. I guess I would have to look into the fill plug hole to see if there is foam inside?

I'll be working on it tonight - I'll post back.

 

[Soundguy]

if you removed the plumping from the pump to the tranny case.. i'd check for a suction leak.

also.. the hyd cover sets atop it's own sump.. if there are leaks between the cyl and cover.. they can spray forward...

 

[strum456]

Say that the lift is weak but slow...does that indicate something different than strong and slow?

 

[Soundguy]

slow and weak would tell me a leak.

slow and strong could be an unload valve not moving into position

 

[strum456]

Here's the report:

As soon as I started the tractor today, the lift was noticeably better. It was still a little slow and jerky, but improved from last night. I hooked it up to a 12' field cultivator and it lifted it. After raising and lowering the cultivator about 50 times, the hydraulics slowly improved back to normal. I guess it was air after all. I thought I used the bleeder and worked it enough last night to get the air out, but letting it sit overnight must have done something.

Thanks again for your input.

 

[Soundguy]

considering it is a 4gpm pump, and there isn't 4g worth of piping and internal valving.. i'd keep an eye on it. might have been an oring seal issue.. and hte oring finally conformed under pressure.